Institute of Electrical Engineers (IEEE) 802.11 networks are currently the most popular wireless local area network (WLAN) products on the market. The technology is mature, and the prices are significantly lower than at its inception. Therefore, IEEE 802.11 products fulfill the needs of many consumers. End consumers use IEEE 802.11 products for mobile networking, both in the residential and business markets, to enjoy undeterred Internet access. Internet Service Providers, realizing the significant cost savings that wireless links offer when compared to classical access techniques (cable and xDSL), embrace the technology as an alternative for providing last mile broadband Internet access. Various companies are using IEEE 802.11 off-the-shelf products to provide wireless data access to devices without a need for special cabling, e.g. remote surveillance cameras, cordless speakers, etc. WLANs make it possible to network historical buildings where it is impossible or impractical to use cables. Researchers in ad-hoc networking are finally offered a high data rate, reliable, low cost implementation radio interface for their testbeds.
A widespread misconception about IEEE 802.11 products regards their throughput. For example, for 802.11b products, their throughput is believed to be 11 Mbps. However, the 11 Mbps so hugely advertised on all IEEE 802.11b products only refers to the radio data rate (of only a part) of the packets. The throughput offered to a user of IEEE 802.11b technology is significantly different. For example, with no transmission errors and 1460 byte sized packets, the throughput of an “11 Mbps” system is just 6.1 Mbps. The efficiency is significantly lower for smaller packet sizes. The efficiency of IEEE 802.11 wireless LANs is in sharp contrast to the efficiency of wired LANs where, for example, a 10 Mbps Ethernet (802.3) link offers users almost 10 Mbps.
The throughput of IEEE 802.11 networks is most often calculated in the absence of transmission errors and for various physical layers, data rates, and packet sizes. The calculation of throughput is more than a simple exercise. It is a mandatory part of provisioning for any system based on 802.11 technology (whether in ad-hoc or infrastructure mode). It is of large practical importance to asses the theoretical maximum throughput for the present applications.
A multitude of variables affect radio-link utilization on 802.11 wireless LAN networks. Finding a concise representation of radio-link performance and utilization has been an on-going problem in this technology, especially while trying to compute the actual average throughput utilization. The methods to asses utilization are only estimative, no matter that individual data packets are transmitted at the same or at a different rate.
What is needed is a method for the exact calculation of throughput and utilization and implicitly an exact assessment about the health of transmission, no matter that the data packets are transmitted at the same or at different rates.